The present invention relates to rotary air lock feeders. This invention more particularly pertains to discharging materials such as insulation in a relatively continuous and even manner.
Rotary air lock feeders typically include a hopper mounted over a cylinder. Material placed in the hopper falls through the hopper down into the cylinder. The material is gravity fed down to a rotor within the cylinder. The rotor has multiple vanes which revolve about an axis in the center of and extending along the length of the cylinder. The material falls between two adjacent vanes that form a revolving chamber. At least four vanes are required to hermetically isolate the hopper from discharge pressure. The cylinder also includes opposing end walls which form mutually aligned inlet and outlet ports. High pressure air passes through the chamber and discharges the material through the outlet port.
Rotary air lock feeders are distinguishable from metering valves because metering valves do not include blowers. In other words, the material passing through metering valves typically passes through a slot running at the bottom of the entire length of the cylinder dependent entirely on gravity, whereas the material passing through a rotary feeder passes through a port at the end of a chamber in an air-train moving from the inlet port to the outlet port and into a hose that conveys the material to a point of application.
Numerous attempts have been made to create a better rotary lock feeder. For example, the rotor might be made to rotate faster to discharge more material but eventually the rotor will reach a point where it spins so rapidly that the material cannot fall in. A longer feeder might be made to accept larger amounts of material to increase the rate of flow of material but they tend to clog and bring the flow to a stop.
In known rotary air-lock feeders, the material then falls into a worm conveyor which is in a trough at the bottom of the hopper. The worm conveyor follows only a portion of the length of the hopper. The remainder includes a multi-vane rotor which substantially corresponds with the length of its cylinder. The multi-vane rotor deflects the material down into fast rotating times within a drop box beneath the hopper in which tines will further separate the material and then allow it to drop into the cylinder.
Brands of fiberglass insulation differ according to weight and compressibility. Some insulation bales break up freely and expand greatly. Others have to be pulled apart and lie flat when separated. Bales of material are dropped into the hopper where paddle wheels in the hopper separate and chew it up.
Light weight, highly compressible material, like some new makes of insulation, expands too greatly to fall quickly into the conveyor of these known machines. The conveyor cannot attack the insulation while it is in large, dense chunks. Rather, it moves light, small, separated bundles of insulation that settle out and fall into it. Consequently, the known machines are slow with this kind of material.
Heavy, dense insulation that is manufactured so as not to expand greatly falls more quickly in known machines. The material, however, accelerates the time to failure of drive train components, feeder seals and rotating elements.
Typically, known feeders have discharge ports which permit gravity to facilitate the movement of the material into the region between the ports rather than permit the speed of rotation of the vanes in the cylinder to introduce the material between the ports, limiting the length of a feeder and thus its capacity and speed. Also, these known feeders often fail to pneumatically isolate the high pressure of the air-train between the ports from the hopper. Escaping air often blows back into the hopper, interfering with and slowing the passage of material from the hopper into the cylinder.
The present invention solves the above-identified problems by providing an improved rotary air lock feeder. The present invention seeks to provide efficient discharging of various types of material, while satisfying the need to discharge the material in a relatively continuous and even manner.
Generally described, the present invention includes a rotary air lock feeder for delivering a material, such as insulation, in substantially an even and continuous manner. The feeder includes a cylinder having a central axis. A multi-vaned rotor is rotatably positioned within the cylinder so that the vanes of the rotor extend radially outward from its axis of rotation which is the center of the cylinder. A hopper communicates with the cylinder through a slotted inlet located in an upper portion of the cylinder for its entire length. A slotted opening offset on one side of the hopper extends along the length of the cylinder.
In accordance with one embodiment of the present invention, the feeder includes a pathway for air at the entrainment pressure from the interior and exterior of the feeder without passing through the outlet port or back through the hopper. The offset opening allows air pressure to escape without going into the hopper where it would interfere with the fall of material.
In accordance with another embodiment of the present invention, to control the introduction of material without significant interference from gravity, the outlet port in the end of the cylinder is defined by outermost and innermost edges defined by increasing and decreasing radii, respectively, relative to the axis of rotation which is the center of the cylinder.
The present invention includes a multi-vaned rotor, unlike a conventional worm conveyor, that does not need a trough in which to operate, and therefore can be placed higher in the hopper to increase the multi-vane""s exposure. To handle extreme kinds of material, the present invention varies the exposure of the multi-vaned rotor to the insulation in the hopper by raising or lowering the multi-vaned rotor""s position in the hopper.
The foregoing has outlined rather broadly, the more pertinent and important features of the present invention. The detailed description of the invention that follows is offered so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter. These form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.